Raising and lowering mechanism



March 14, 1944. COHEN RAISING AND LOWERING MECHANISM Filed Jan. 6, 1943 2 Sheets-Sheet 1 WW WW i mhr INVENTOR WITNESSES Harold Cohen/ m %6 /azaa? ORNEYS March 14, 1944. col-{EN RAISING AND LOWERING MECHANISM Filed Jan. 6, 1943 2 Sheets-Sheet 2 mm 7 Wm w in NM. mm

INVENTOR wn mssses .Jfar'Old Cohen m BY \7( l 4 a S r 7 A ORNEYS Patented Mar. 14, 1944 parts STATES" OFFICE This invention relates to a mechanism for causing the movement of a structure between predetermined limits, that is to say, to raise and lower the structure, or to move it from one position into another and vice versa.

The invention contemplates the movement of a movable structure which is initially moved or boosted out of a dead center position and then fully or completely moved into the other position, together with suitable means for the application of power to cause the initial movement augmented by the action of gravity, and also to completely move the structure to the desired position.

The principal object of the invention is the provision of a mechanism of the indicated character which facilitates the movement of a structure from one position into another and minimizes the force required for causing such movement, which may be characterized as an opening and closing movement, a raising and lowering movement, or any other movement in which a structure in one position is moved into another position and vice versa, and in cases where the structure is in the form of mast, ladder, stairs, grille, chute, fixture, base member, door, window, cover, panel and others. V With the foregoing, other objects of the invention will appear from the following specification describing one embodiment thereof, the appended claims defining the scope of the invention, and the accompanying drawings illustrating the invention by Way of example.

In the drawings- Fig. l is a perspective view of a portable mast selected to illustrate the features of the invention;

Fig. 2- is a longitudinal section showing the mast in its fully lowered position;

Fig. 3 is a view similar to Fig. 2 showing the mast boosted or partly raised from its lowered position so that it may be completely moved intotion so that it may be completely moved from the lowered, position into a raised position. Suitable power means l4 serves for the application of force to operate the booster l3 and also to move the mast l0 into the raised or up position and said means 14 is operable to control the movement of the mast from the raised to the lowered or down position.

The mast I0 comprises a main section l5 and a leg section 16. The main section l5 consists of upper and lower portions I1 and I8, respectively, which are disposed at an obtuse angle with respect to each other. The leg section It has its upper end pivotally. connected, as at IS, with the main section I5 intermediate the ends thereof or approximately at the juncture of the portions H and it. The lower end of the leg section It is pivotally connected, as at 20, with the deck H. In this manner the main section I5 is movably connected and subject to the angular movement of the leg section Hi. The lower portion [8 of the main section I5 and the leg section l6 constitute supports for the upper portion H of the main section l5 when the mast is in the raised or up position as shown in Fig. 1. The sections [5 and t6 are so proportioned and connected that they move under'the action of gravity out of their up relation to a down relation to thereby lower the mastto the down position.

The booster I3 for boosting or initiating the movement of the mast l0 out of its lowered position, in the present instance, consists of a rocker or bell-crank lever having arms 2| and 22, respectively, and a fulcrum or pivot 23. The pivot 23 is supported by suitable bearings 24 secured to the deck H. The arm 2| carries a roll 25 at its free end, the arm 22 carries a sheave 26 at its free end, and a guide sheave 21 is loose on the pivot 23. An abutment 28 is secured to the main section {5 approximately at the juncture between the upper and lower portions I! and !8 thereof. The booster or bell-crank lever I3 is operable to partly move the mast I0 out of its down position so that it may be completely moved out of the down position into the raised or up position. The roll 25 on the arm 22 is engaged by the abutment 28 and thus sets the booster I3 into its boosting position as the mast 10 moves into the lowered or down position.

In the movement of the mast ID, the lower end 01' the main section l5 rides on a track consisting of spaced parallel rails 29 secured to the top of the deck II. The lower end of the main section I5 carries an axle 30 having wheels 3! on the opposite ends thereof which roll on the rails 29 respectively. Each of the rails 29 has a downwardly curved or inclined end portion 32. These portions 32 help to initiate boosting of the mast, although they are not absolutely necessary for the effectual operation. By providing the end portions 32, the lower end Of the main section will move downwardly under the action of gravity as the main section I5 moves laterally in the boosting operation.

When the mast I is in the lowered or down position, the sections I and I6 thereof bear such relationship that the lower portion I8 of the main section I5 is in dead center relation to the leg section I6, as shown in Fig. 2. In this relationship the booster I3 is set in its boostin or raising position with th roll in engagement with the abutment 28 and the booster may be operated.

for the intended purpose.

The power means It serves for the application of force to operate the booster I3 and also to move the mast into the up or raised position,

and such means I4 is operable to control the movement of the mast from the raised to the lowered position. In this movement of the mast the sections I5 and I6 thereof assume the down relationship under the action of gravity when the holding force which maintains the mast in the raised position is withdrawn. The power means I4 consists of a winch 35 having a drum 36 operated by means of cranks 31 geared to the drum by gearing 38. A suitable ratchet 39 is provided to check the rotation of the drum 35. A cable 49 has one end secured to the drum 36 and its other end is secured to th axle 30 as at M. It will be obvious that by operatin the cranks 31 the cable may be wound on the drum 35 or be permitted to unwind therefrom. The cable passes over the sheave 26 on the arm 2| and under the sheave 21, as shown most clearly in Figs. 2 and 3. The winch 35 is arranged on the top of the deck II, and it is to be understood that it may be arranged in any other desired position. It is also to be understood that any other suitable power device may be employed instead of the winch 35, such as an electric motor.

When the parts are in the relationship shown in Fig. 2 in which the mast is in the lowered position, the operation is as follows. The cranks 31 are operated to cause the rotation of the drum- 36 counterclockwise. This causes the cable w, in contact with the sheave 26, to bear down on the arm 2I of the booster I3 causing the arm 22 to move upwardly with the roll 25 in contact with the abutment 28. The cable 40 exerts a downward pressure to operate the booster I3 because the main section I5 cannot move laterally at the moment of the application of the downward pressure of th cable. After the lower portion I8 is out of the dead center relation with respect to the leg section I6, 2, pulling force-is then exerted by the cable 40 on the axle 3i] supplemented by the downward movement of the lower end of the section I5 under the action of gravity in which the wheels 3| ride down on the end portions 32. As the drum 36 continues to rotate the main section I5, guided along the rails 29 and also by the leg section I6, moves upwardly from the boosted position, as shown in Fig. 3, into the fully raised position, as shown in Fig. 1. The ratchet 39 is then brought into pla tohold the drum 36 againstrotation. As a consequence, the mast I 0 will be maintained in the raised position in which the leg section I6 and the lower portion I8 of the main section I5 serve as supports for the upper portion I? of the. main section I5.

When it is desired to lower the mast Ifljto. the down position the ratchet 39' is released; after which the; cranks; 37 1 are enerated to: permit: the

drum 36 to rotate slowly in a clockwise direction to pay out the cable 40, thereby enabling the sections I5 and I6 to move under the action of gravity until the sections I5 and I6 are at rest, thus bringin the mast to the lowered position.

In Figs. 2 and 3 the sections I5 and I6 of the structure I0 are conventionally illustrated as compared with the frame work shown in Fig. 1. The section I6 as shown in Fig. 1 consists of two parts in order to provide clearance for the cable 40. While the structure II] in the present instance is shown in the form of a mast, it is to be understood that the structure I0 may be in the form of a ladder, stairs, grille, chute, fixture, base member, door, window, cover, panel and others, as hereinabove mentioned.

I claim:

1. The combination of a mast which may be moved. to a raised position and a lowered position, and raising and lowering mechanism for the mast, said mast consisting of a main section and a leg section, said main section consisting of upper and lower angularly disposed portions respectively, said leg section having one end pivotally connected with said main sectionintermediate the ends thereof and the other end being pivotally connected with a fixed part, said lower portion of the main section and the leg section constituting supports for the upper portion of the mainsection when the mast is raised, said mechanism including a bell-crank. lever operable to partly move the main section out of dead center relation with respect to the leg section when the mast is in the lowered position, so that it may be completely moved into the raised position, and means engageable with the lever and. connected withthe main section to operatethe lever and also apply force to the main section to completely move the mast to its raised po ition.

2. The combination as set forth in claim 1, and a track on which the lower end of the lower portion of the main section of the mast rides in the raising and lowering operations.

3. Thecombination as set forth in claim 1, wherein said means consists of a cable, and a power device to operate the cable.

4. The combination with a structure connected for movementbetween one position and another, of a-bell-crank lever operable to partly move the structure out of one position, andmeans to 0pthe other end being pivotally connected with a fixed part, of a bell-crank lever operable in conjunction wit'n'said main section to move it out'of up position and a down position, of a bell-crank lever, and a cable, said cable-engaged with one end of said lever andthe other end of said lever bearing on said structure in order'to partly move 8. The combination as set forth in claim 4, and a. horizontal track having an inclined portion, one end of said main section riding on said inclined portion so that said end of the main section may 6 move initially downwardly and horizontally and then continue to ride along said track.

HAROLD COHEN. 

